Merge branch 'tpmdd-next-v3.6' of git://github.com/shpedoikal/linux into for-linus

1 files changed, 14 insertions, 7 deletions

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index b429f1ea1b97..93211df52aab 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -1182,17 +1182,20 @@ ssize_t tpm_write(struct file *file, const char __user *buf,
                   size_t size, loff_t *off)
 {
         struct tpm_chip *chip = file->private_data;
-        size_t in_size = size, out_size;
+        size_t in_size = size;
+        ssize_t out_size;
 
         /* cannot perform a write until the read has cleared
-           either via tpm_read or a user_read_timer timeout */
-        while (atomic_read(&chip->data_pending) != 0)
-                msleep(TPM_TIMEOUT);
-
-        mutex_lock(&chip->buffer_mutex);
+           either via tpm_read or a user_read_timer timeout.
+           This also prevents splitted buffered writes from blocking here.
+        */
+        if (atomic_read(&chip->data_pending) != 0)
+                return -EBUSY;
 
         if (in_size > TPM_BUFSIZE)
-                in_size = TPM_BUFSIZE;
+                return -E2BIG;
+
+        mutex_lock(&chip->buffer_mutex);
 
         if (copy_from_user
             (chip->data_buffer, (void __user *) buf, in_size)) {
@@ -1202,6 +1205,10 @@ ssize_t tpm_write(struct file *file, const char __user *buf,
 
         /* atomic tpm command send and result receive */
         out_size = tpm_transmit(chip, chip->data_buffer, TPM_BUFSIZE);
+        if (out_size < 0) {
+                mutex_unlock(&chip->buffer_mutex);
+                return out_size;
+        }
 
         atomic_set(&chip->data_pending, out_size);
         mutex_unlock(&chip->buffer_mutex);